All stuff to try when looking to improve combustion......
How to Pick the Best Carburetor for a Street/Strip Car
Have to laugh when the smaller carb ran quickest and idles best its 425 CI on street fuel:
As you can see from the Dragstrip Test Results chart, our guess that the 650 carburetor might run the quickest of the bunch turned out to have some validity. The smaller carburetor delivered the quickest move to the 330-foot mark and the quickest overall e.t. and fastest mph
I wonder what that's telling you this engine needs......what does the smaller carb do?
It needs to use more of the fuel it already gets......